: While the prefrontal cortex—responsible for impulse control—is largely developed by 25, the brain remains plastic and capable of significant cognitive maturation long after.

: Physical maturity often hits earlier for girls than boys, though researchers from the Genetic Literacy Project investigate whether this leads to earlier cognitive maturation as well. 2. Emotional and Social Indicators

: Research from Jackson Health indicates that the brain moves through five distinct stages of development, only fully stabilizing in a person’s early 30s .

: Many adults report a "faulty give-a-f***" in their 30s, where they stop prioritizing others' opinions over their own values. 3. The "On-Paper" vs. "Emotional" Gap